Wooden dual panel sound insulating structures



WOODEN DUAL PANEL SOUND INSULATING STRUCTURES Filed Feb. 26, 1968 P. E. SHERMAN Aug. 26, 1969 5 Sheets-Sheet 1 IN EN I QR P/NY/JO 5 Sher/77w,

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Aug. 26, 1969 P. E. SHERMAN 3,462,899

WOODEN DUAL PANEL SOUND INSULATING STRUCTURES m 3 mm t Tr W %6 @T h? V T g 33 N5 y S (QA/ wow 5 M E w 4 I. v h i P ,9 Y 3 B m. 3 4 vfl 7 d4 i F 8 6 9 1 M: F mm 4 n5 F Aug. 26, 1969 P. E. SHERMAN 3,462,399

WOODEN DUAL PANEL SOUND INSULATING STRUCTURES Filed Feb. 26, 1968 5 Sheets-Sheet 4 566 FJ-S 5 400 5 i5 5 F LEA 400 320 325 INVENTOR.

F5 nyPhf/l 'n E. 5/) erman 6, 1969 P. E. SHERMAN 3,462,899

WOODEN DUAL PANEL SOUND INSULATING STRUCTURES Filed Feb. 26, 1968 5 Sheets-Sheet 5 Fig 1.3 1% 66 75 56 2a a 5 0 @Z 75 65 ii M INVENTOR.

Phf/ E. 5/70777 /7 HTTORNE Y United States Patent 3,462,899 WOODEN DUAL PANEL SOUND INSULATING STRUCTURES Philip E. Sherman, 9060 Union Turnpike, Glendale, N.Y. 11327 Filed Feb. 26, 1968, Ser. No. 708,109 Int. Cl. E04b 1/84 U.S. Cl. 52-309 18 Claims ABSTRACT OF THE DISCLOSURE Wooden dual panel sound insulating structures comprising a main panel member and a floating panel member, said panel members having inner face spans of different sizes and thicknesses, said face spans each being covered with layers of different and independent sound insulating materials, the peripheral edges of the panel members being covered with independent edge bands, said edge bands being secured fixedly to one of said panel members and being flexibly linked to the other of said panel members by means of splines adapted to be received within insulated peripheral slots, whereupon, there is a total and complete separation of the panels on their inner sides with no rigid point of contact whatsoever therebetween, whereby sound vibrations striking one outer face panel member cannot be transmitted into the other panel member without first penetrating through several layers of varying sound vibration insulating materials.

BACKGROUND OF THE INVENTION Field of the invention The invention relates generally to sound insulating structures, and particularly to doors, partitions and windows, wherein there is a main frame panel member and a floating frame panel member having internal free spans of different sizes and thicknesses and a total and complete separation of their rigid parts, whereby sound vibrations striking one panel member cannot be transmitted directly into the other panel member without first penetrating through several layers of varying sound vibration insulating materials.

Description of the prior art There is shown in United States Letters Patent No. 2,880,471, issued Apr. 7, 1959, sound insulating structures consisting of a main frame, an intermediate frame and a secondary frame having free spans of different sizes and being separated along the outer perimeter with a sound vibration insulating material.

United States Letters Patent No. 3,051,260, issued Aug. 28, 1962, discloses a compartmented steel door in which the opposite compartments are separated by a limp septum of high density material, such as rubber.

United States Letters Patent No. 3,159,235, issued Dec. 1, 1964, shows an acoustical partition having a compartment filled with a blanket of low density fibrous glass, which, in turn, is mounted on a backing or septum of kraft paper, and the blanket is folded with the fibrous material facing outwardly to readily receive the sound and the kraft backing paper in the middle forms a pair of sound blocking septa.

In the aforementioned prior art involving a main frame and a second frame, such frames are made rigid and are in direct contact with each other, providing a direct passageway through the structures for vibrating sound waves, thereby reducing the effectiveness as a sound insulating structure. Such direct passageways have been obviated by the present invention, and the need for a third intermediate frame has also been eliminated.

3,462,899 Patented Aug. 26, 1969 SUMMARY An object of the present invention is to provide a light weight soundproof structure of the character described, which is simple, efficient and economical to manufacture and install.

Another object of the invention is the provision of a soundproof structure of the character described, which is compact, similar in size and appearance to a conventional door or movable partition, and which is easy to manipulate for hanging and for opening or closing since it is exceedingly light-in-weight as compared to existing sound insulating structures.

A further object of the invention is the provision of a flexible dual panel sound insulating structure in which there is complete and total separation between the panels with no rigid point of contact therebetween.

Another object of the invention is to provide an arrangement of different sound resisting materials on the different panels, particularly over their respective free spans, thereby causing the natural frequency responses of each panel member to react differently and independently of each other to achieve a better soundproof barrier therebetween.

A further object of the invention is the provision of a sound insulating structure formed of dual panel members which, when combined, have no rigid point of connection, but, because of the construction, provides a limp and flexible structure, having the qualities and characteristics of absorbing sound waves as they come into contact therewith.

Another object of the invention is to provide a sound insulating structure formed of dual panel members which can be moved with respect to one another even after assembly, which flexibility attests to the limpness of the assembled structure and improves the soundproofing qualities thereof.

Another object of the invention is to provide suitable sealing edge bands which are secured to the peripheral edges of one panel member, and, which, in turn, have outwardly protruding splines adapted to fit into insulated receiving grooves in the peripheral edges of the other panel members, thereby interlocking and securing the two' panel members together into an integrally formed assembly while retaining complete and total separation to insure and preserve the soundproof and/or acoustical values thereof.

Other and further objects and advantages of the invention reside in the detailed construction of the several panel members, which result in simplicity, economy and efliciency, and which will be apparent from the following description, wherein preferred embodiments of the invention are shown, reference being had to the accompanying drawings, forming a part hereof, wherein like numerals indicate like parts, in which:

DRAWINGS FIGURE 1 is a front elevational view of a sound in sulating structure in the form of a door shown mounted in a conventional door frame, which has been constructed in accordance with the principles of the invention and which has parts thereof broken away to better illustrate the features thereof;

FIGURE 2 is a vertical sectional view of the structure shown in FIGURE 1, the same having been taken substantially along the line 2-2 thereof, looking in the direction of the arrows;

FIGURE 3 is a cross-sectional view of the structure shown in FIGURE 1, the same having been taken substantially along the line 3-3 thereof, looking in the direction of the arrows;

FIGURE 4 is an enlarged fragmentary detailed view of the door and header shown in FIGURE 2;

FIGURE 5 is a fragmentary vertical sectional view of a modification of the structure shown in FIGURE 1, wherein the base is constructed to fit a fiat sill;

FIGURE 6A is a fragmentary cross-sectional view of a modified form which the invention may assume, wherein a pair of swinging doors are shown with their astragal detail fo sealing the intermediate space therebetween;

FIGURE 6B is a fragmentary cross-sectional view of one of the doors shown in FIGURE 6A, showing its vision port and the details of its construction;

FIGURE 7 is a front elevational view of a modified form of sound insulating structure in the form of a door of greater thickness mounted in a conventional door frame, which has been made in accordance with the prin ciples of the invention and which has parts thereof broken away to better illustrate its features of construction;

FIGURE 8 is a vertical sectional view of the structure shown in FIGURE 7, the same having been taken substantially along the line 88 thereof, looking in the direction of the arrows;

FIGURE 9 is a cross-sectional view of the structure shown in FIGURE 7, the same having been taken sub stantially along the line 9-9 thereof, looking in the direction of the arrows;

FIGURE 10 is an enlarged fragmentary detailed view of the door and header shown in FIGURE 8;

FIGURE 11 is a fragmentary vertical sectional view of a modification of the structure shown in FIGURE 7, wherein the base is constructed to fit with a flat sill; 1

FIGURE 12A is a fragmentary cross-sectional view of a modified form which the invention may assume, wherein a pair of swinging doors are shown with their astragal detail for sealing the intermediate space therebetween;

FIGURE 12B is a fragmentary crosssectional view of one of the doors shown in FIGURE 12A, showing its vision port and the details of its construction;

FIGURE 13 is a cross-sectional view of a modified form of door, similar to FIGURE 3, but showing the edge bands being mounted on the floating frame panel member with its splines extending into the main frame panel member, which is the reverse of the construction shown in FIGURE 3; and

FIGURE 14 is a cross-sectional view of a modified form of door, similar to FIGURE 9, but showing the edge bands being mounted on the floating frame panel member with its splines extending into the main frame panel member, which is the reverse of the construction shown in FIGURE 9, and including a different type of limp material in the floating frame panel member for higher acoustical values.

DESCRIPTION OF THE INVENTION (I) Dual panel door of 1%" thickness Referring now to FIGURES 1 through 5, there is shown the construction of a sound insulating structure in the form of a wooden dual panel door, which is approximately one and seven-eighths inches thick by three feet wide and seven feet high, comprising a main frame member 10 and a floating frame member 12. The above thickness dimension shows clearly the improvement in the present sound insulating structure since the thickness of the present door is less than one-half of the thickness and weight of present day soundproof doors while its sound insulating properties are substantially as great if not better in most instances.

The main frame.The main frame member 10 is always the heavy or the hinge side of the door, and comprises stiles 16 and 18 and rails 20 and 22 made of conventional chipboard formed integrally into a rectangular frame, and reinforced at the corners with corrugated nails 23. There is an opening or free span 24 centrally of the main frame member 10. A plywood panel 26 is mounted on the outer face of the main frame member 10 by gluing the same to the outer surfaces of its stiles 16 and 18 and rails 20 and 22, which plywood panel member completely covers the central opening 24. A second plywood panel member 28 is glued to the opposite or inner face of the main frame member 10, and has an opening 30 corresponding in size and shape to the central opening 24 in the main frame member 10. By gluing the plywood panels 26 and 28 to the opposite sides of the main frame member 10, there is no chance of warping said frame member during the drying period of the glue, which can readily occur if only one side is paneled with a plywood facing member.

A layer of conventional viscous damping material 32, such as a conventional caulking compound, is now ap plied to the inner surface of the plywood panel member 26 coextensive with the opening 24 in the main frame member 10 to substantially the thickness of the rails and stiles. A panel of conventional sheet rock material 34 of approximately the thickness of the plywood inner panel 28 is now placed over the layer of viscous damping material 32 to completely fill said opening 30. A membrane of conventional roofing tar paper 36 is positioned over the inner surface of the main frame member 10, covering the sheet rock material 34 and extending beyond the edges thereof and over the outer surface of the second or inner plywood panel 28. The tar paper membrane 36 is attached only by conventional staples 38 to an intermediate point of the inner plywood panel 28.

The floating frame-The floating frame or sub-frame member 12, comprising stiles 42 and 44 and rails 46 and 48, is also formed of conventional chipboard into a rectangular structure, and the corners thereof are reinforced by corrugated nails 23 in the same manner as shown in FIGURE 1. The floating frame member 12 has a larger central opening 50 than the openings 24 and 30 in the main frame member 10, but it is of a similar rectangular shape. These differences in the openings or free spans of the frame members 10 and 12 cause a difference in the natural frequencies between the frame members 10 and 12 both as to free span and mass, thereby providing a difference in the natural frequency responses, preferably disharmonic-the thing called beat, which, as the physicists know, inhibits the transmission of vibrations from one taut string or one vibrating panel to another by what is often called sympathetic resonance. A plywood panel member 52 is mounted on the outer face of the chipboard floating frame member 12 by gluing the same to the outer surfaces of the stiles 42 and 44 and rails 46 and 48, which plywood panel member completely covers the central opening 50. The lower edge of the plywood panel 52 projects downwardly below the bottom edge of the door, as indicated at 53, a distance equal to the bottom edge of its opposing encircling edge band. A second or inner plywood panel 54 is glued to the inner face of the chipboard floating frame member 12, having an opening 56 therein corresponding in size and shape to the central opening 50. The simultaneous gluing of the panels 52 and 54 to the opposite surfaces of the chipboard floating frame member 12 eliminates any warping of the assembly during the drying of the glue since there are corresponding drying pressures on the oppositesides thereof. A thick layer of conventional viscous damping material 58 is now applied to the exposed inner surface of the plywood panel member 52, filling the central opening 50 in the chipboard floating frame member 12 approximately one-half way, and a panel of conventional paper covered polyurethane material 60 is next placed over the layer of viscous damping material 58. The paper covered polyurethane material 60 is of a thickness suflicient to completely fill the remainder of said opening 50- in the floating frame member 12 and the corresponding opening 56 in the second or inner plywood panel member 54, thereby presenting a level surface on the inner side of the floating frame member 12.

Assembling the main frame and floating frame.The dual panel members forming the main frame and the floating frame 12, respectively, of the sound insulating structure, are now ready to be assembled. The main frame member 10 is positioned horizontally with the outer face panel 26 facing downwardly. A layer of conventional open cell foam rubber sheeting 62 is mounted over those portions of the second or inner plywood panel 28 extending beyond the edges of the tar paper membrane 36. The open cell foam rubber sheeting 62 also extends slightly beyond the edges of the frame structure 10, as indicated at 63 and best shown in FIGURE 3. It will be noted that the extended portion of the foam rubber sheeting 63 is under greater compression since the space it occupies is of a less height. Thereupon, the floating frame member 12 with its outer face panel 52 extending upwardly is superimposed upon the main frame member 10. It will be noted that, in this assembled position, there is no direct contact between the rigid portions of the main frame member 10 and the floating frame member 12. Hence, there can be no direct transmission of vibrations from one frame member to the other frame member. Any vibrations striking the outer surfaces of the panels 26 and/or 52 must be passed through the various nonharmonic damping and soundproofing materials. It will also be noted, in the assembly, as best shown in FIG- URE 3, that there is an air space 65 substantially coextensive with the surface area of the tar paper membrane material 36, providing an additional sound insulating barrier.

With the main frame member 10 and the floating frame member 12 assembled in superimposed relationship, the assembly is now ready to receive suitable vertical edge bands 66 and 68 and horizontal edge bands 70 and 72.

The vertical edge bands 66 and 68 are best shown in FIGURES 1 and 3. The edge bands 66 and 68 have a portion thereof glued, as indicated at 69, to the side edges of the main frame member 10. The floating frame member 12 is completely separated from the edge bands 66 and 68 by the projecting ends of the foam rubber sheeting 63. It will be further noted that the stiles 42 and 44 of the floating frame member 12 are recessed, as indicated at 71. A U-shaped rubber extrusion member 73 is mounted in each of the recesses 71 with its arms opening outwardly to provide a sound insulated receiving slot. The edge bands 66 and 68 are each provided with a wooden spline 78 fixedly mounted therein, as by gluing, with a portion thereof projecting outwardly there from, as best shown in FIGURE 3. The protruding portions of the splines 78 are inserted frictionally into the receiving slots of the rubber extrusion members 73, forming the only link between the edge bands 66 and 68 and the rails 42 and 44 of the floating frame member 12. It will further be noted that an air space 80 extends between the edge bands 66 and 68 and the floating frame 12 outwardly of the splines 78 to the door face.

The horizontal edge bands 70 and 72 are best shown in FIGURES 2, 4 and 5. The edge bands 70 and 72, like the edge bands 66 and 68, have a portion thereof glued, as indicated at 69, to the side edges of the main frame member 10. The floating frame member 12 is completely separated from the edge bands 70 and 72 by the projecting ends of the foam rubber sheeting 63. It will be noted that the rails 46 and 48 of the floating frame 12 are recessed, as indicated at 84. A U-shaped rubber extrusion member 73 is mounted in each of the recesses 84 with its arms opening outwardly to provide a receiving slot. The edge bands 70 and 72 are each provided with a wooden spline 78 fixedly mounted therein, as by gluing, with a portion thereof projecting outwardly therefrom, as best shown in FIGURE 4. The protruding portions of the splines 78 are inserted frictionally into the receiving slots 71 of the rubber extrusion members 73, forming the only link between the edge bands 70 and 72 and the stiles 46 and 48.

Peripheral door seals.There is shown in FIGURES 3 and 4 a sealing gasket 104, which is substantially rectangular in cross-section, for effectively sealing the top peripheral edge of the door with its conventional door frame 106. The sealing gasket 104 consists of a piece of ultra soft foam rubber 108 encased in a plastic wrapper or cover 110 having outwardly extending flanged ends 112. The flanged ends 112 are adapted to be secured by staples 114 between the door frame 106 and the door stop 116.

Referring again to FIGURE 2, there is shown the details of the sealing of the bottom edge of the door against a sloping sill 120. In this arrangement, the edge band 72 has a notch or step cut therein, as indicated at 122, to provide a recess or receiving slot for securing a sealing gasket 124 thereto. The sealing gasket 124 has flanged ends 126, and is secured in the receiving slot 122 by means of a wooden strip 128, which, in turn, is secured by a screw passing through the stop 128 and into the edge band 72.

Referring now to FIGURE 5, there is shown the details of the sealing of the bottom edge of the door against a flat sill 140. In this arrangement, the edge band 72 is notched or recessed, as indicated at 142. The notch or recess 142 is fitted with a conventional adjustable drop seal 144. The protruding sealing strip 146 is slidably adjustable in the drop seal 144 to seal off the opening at the door bottom.

There is also shown on the right side of FIGURE 3 an effective seal for sealing the hinged side of the door. In this arrangement, a wedge or flat foam rubber strip is mounted in any suitable rnanner, as by gluing, on the inner surface of the door stop 174. A thin plywood strip is secured to the inner side of the door stop 174 and secures the flanged ends of the sealing gasket 176 thereto. An angular L-shaped door stop 174, having a sealing gasket 176, is mounted over the inner side of the foam rubber strip 170 and suitably secured thereto in any suitable manner, as by gluing. The sealing gasket 176, when the door is closed, becomes wedged between the edge band 68, the foam rubber strip 170 and the inner end of the door stop 174. The opposite side of the (II) A pair of swinging doors There is shown in FIGURE 6A a modification of the present invention in the form of a pair of swinging doors 201 and 203. The doors 201 and 203 are each provided with a vision port or window 205, which is partially shown in detail in FIGURE 63.

The vision port or window 205 consists of two independent panes of plate glass 210 and 212 suitably secured in window mouldings 214 and 216, one being mounted to the main frame member 10 and the other being mounted to the floating frame member 12. The window mouldings 214 and 216 have a recess or slot 218 cut therein into which is fitted a U-shaped rubber extrusion member 220 with its arms extending outwardly to the surface of the mouldings 214 and 216. The panes of glass 210 and 212 are mounted with their peripheral edges extending into the slots 222 between the arms of the rubber extrusion member 220. Across the inner surfaces of the inner peripheral edges of the window frames 214 and 216 and between the spaced glass panes 210 and 212 there is glued a felt liner 224.

There is shown in FIGURE 6A an astragal detail for effectively sealing the pair of swinging side edges. It will be noted that the opposing edge bands 226 and 228 do not meet or touch each other, but are slightly separated by an air space 230, which acts as clearance on pairs of swinging doors.

There is mounted on the floating frame member 12 in any suitable manner, as by gluing, fasteners and the like (not shown), a strip of wood 231, which extends the entire height of the door. The strip of wood 231 is notched or recessed, as indicated at 233, and has a rubber extrusion member 235 suitably secured therein. The extrusion member 235 has a semi-circular protuberance 237, which is adapted to extend into the air space 230 and .into contact with the opposing sides of the opposing edge bands 226 and 228.

Referring now to FIGURE 13, there is shown another modified form of an inch and seven-eighths inch wooden dual panel door, which is substantially identical in every respect to the one and seven-eighths inch door shown in FIGURES 1 through 6, both inclusive, except that, in this modification, the vertical edge bands 66 and 68 and the horizontal edge bands 70 and 72 (the latter not shown) are mounted directly on the peripheral edges of the floating frame member 12, and the ends 63 of the foam rubber sheeting 62 are turned oppositely to that shown in FIGURE 3 and over the adjacent peripheral edge of the main frame member 10. The U-shaped rubber extrusion members 73 are now mounted in recesses 71 in the main frame member 10. The protruding portions of the splines 78 are now inserted frictionally into the receiving slots of the rubber extrusion members 73 mounted in the peripheral edges of the main frame member 10. The air space 80 now extends between the edge bands 66 and 68 and the adjacent edges of the main frame member outwardly to the door face.

(III) Flexibility of the structures of the 1% doors The aforementioned dual panel doors, even after assembly, are exceedingly flexible and tend to become a limp panel having the qualities and characteristics of being more soundproof because its limpness acts as a barrier to sound and has a tendency to absorb more intensely the energy of the sound waves as they come into contact therewith.

The dual panel doors hereinabove described, when assembled, have an overall thickness of one and seveneighths inches. The relatively thin chipboard bases of the main frame and the floating frame are approximately three-eighths of an inch in thickness, and have two relatively thin plywood panels in the order of one-fourth of an inch in thickness mounted on opposite sides thereof. The layers of viscous damping material 32, which are applied to the inner faces of each outside panel, are in the order of one-fourth of an inch in thickness, and the remainder of the free spans of the main panel member 10 above the viscous damping material is filled with a sheet rock panel 34 of approximately one-half of an inch in thickness. In the floating frame member 12, the layer of viscous damping material 58 is covered with a sheet of paper covered polyurethane material 60 in the order of three eighths of an inch in thickness. A middle membrane of felt roofing tar paper 36 is attached by staples 38. to the inner main frame panel, and a foam rubber sheeting extends from the ends of the tar paper membrane 36 over the remaining portions of the main panel member and into end grooves of the floating frame assembly. Thus, the free span cavities of the dual panels are completely filled. The only unfilled spaces are immediately above the felt tar paper membrane 36 and along the peripheral edges beyond the interlocking wooden splines. These spaces and the cellular foam rubber sheeting provide breathing slots that permit the assembled doors to absorb and discharge humidity involved in different atmospheric conditions. This single but most effective solution renders the door assemblies virtually warp-proof throughout their lifetime.

The assembled door units, as a Working installation, are flexible and not stiff panels. In other words, the assembly is limp and can be easily twisted, flexed or bent to almost any desired degree. If'one corner was to be picked up,

8 the bend or twist of the assembled structure is very noticeable to the eye of an average observer. Obviously, sound waves that are bounced against a door panel of such limpness will be distorted, and hence are less likely to be of a transmissive nature than if bounced off or against a stilf and solid reflective surface like that of an ordinary door or the doors or partitions of the prior art.

The flexibility of the assembled door units can further be demonstrated by applying lateral pressure to the peripheral sides or ends thereof. When such pressure is applied to the assembled unit, the frame member carrying the recesses and insulated receiving slots may be moved longitudinally or laterally with respect to the frame member carrying the splines. Such movements can be effected upon the application of pressure even after the door is hung. In other words, these assembled structures have no rigidity in the normal sense at any time.

(IV Modified 2 /3 dual panel door There is shown in FIGURES 7 through 12 and 14 a modified dual panel sound insulating structure in the form of a wooden dual panel door, which is two and five-eighths inches thick by three feet wide and seven feet high, comprising a main frame member 310 and a floating frame member 312.

The main frame.-The main frame member 310 is always the heavy or hinge side of the door, having the smaller free span between the stiles 316 and 318 and rails 320 and 322, which stiles and rails are made of conventional chipboard and formed integrally into a rectangular frame. The stiles and rails are glued together and have their corners reinforced with corrugated nails 324. A plywood panel 326 is mounted on the outer face of the main frame member 310 by gluing the same to the outer surface of its stiles 316 and 316- and rails 320 and 322, which plywood panel member completely covers the central opening or free span 323. A second plywood panel member 328 is glued to the inner face of the main frame member 310, and has an opening 330 corresponding in size and shape to the central opening 323 in the main frame member 310.

A relatively thin layer in the order of one-fourth of an inch in thickness of conventional viscous damping ma terial 332, such as a conventional caulking compound, is now applied to the inner surface of the plywood panel member 326. A thicker layer of approximately threeeighths of an inch of conventional sheet rock material 334 is now placed over the layer of viscous damping material 332. A layer of conventional mineral material 336 is next placed over the layer of sheet rock material 334 to a thickness of approximately two inches, which is suflicient to evenly fill the free span opening 330' flush with the inner face of the panel member 328. A sheet of conventional felt tar paper 338 is now placed over the top of the mineral material 336, and is secured in any suitable manner, as for example 'by staples 340, to the edges of the inner plywood panel member 328 adjacent the peripheray of the free span opening 330.

The floating frame.-The floating frame or sub-frame member 312, comprising stiles 342 and 344 and rails 346 and 348, is also formed of conventional chipboard into a rectangular structure Whose corners are also reinforced With corrugated nails 324. The floating frame 312 has a central opening 350, which is larger in size than the corresponding opening 330 of the main frame memher 310, but is of a similar shape.

A plywood panel member 352 is mounted on the outer face of the chipboard floating frame member 312 by gluing the same to the outer surface of its stiles 342 and 344 and rails 346 and 348, which plywood panel member completely covers the central opening 350.

A second or inner plywood panel 354 is glued to the inner face of the floating frame stiles 342 and 344 and rails 346 and 348, having an opening 356 therein corresponding in size and shape to the central opening 350.

The simultaneous gluing of the panels 352 and 354 to the opposite surfaces of the stiles 342 and 344 and the rails 346 and 348 eliminates any warping of the assembly during the drying of the glue. A layer of viscous damping material 358 in the order of one-fourth of an inch in thickness is now applied to the exposed inner surface of the plywood panel member 352, filling a portion of the opening 350. The remainder of the free span space is then filled with a layer of paper faced styrene 360.

Assembly of the main and floating frames-The main frame 310 and floating frame 312 are assembled in the same manner as that previously described for the main and floating frames 10 and 12 of the one and seven-eighths inch dual panel doors. However, in this modification, a sheet of conventional open cell foam rubber 365 is positioned between the main frame and floating frames at the time of assembly. The foam rubber sheeting 365 is mounted over those portions of the second or inner plywood frame 354 extending beyond the edges of the tar paper membrane 338. The open cell foam rubber sheeting 365 also extends beyond the edges'of the frame member 312, as indicated at 367. It will be noted that the extended portions of the foam rubber sheeting 367 are under greater compression than the main portion 365 since the space it occupies is of less height. An air space 369 is provided between the main frame member 310 and the floating frame member 312 and between the inner opposite edges of the foam rubber sheeting 365 and coextensive and contiguous to the inner surface of the tar paper 338.

The assembled structure is also provided with a series of vertical edge bands 366 and 368 (see FIGURE 9) and horizontal edge bands 370 and 372 (see FIGURE 8). In each instance the edge bands are glued, as at 331, onto the periphery of the main frame member 310 and are provided with suitable fixed wooden splines 374, which, in turn, protrude outwardly therefrom and are adapted to fit into a slotted recess in an extruded U- shaped rubber member 376 mounted fixedly in the vertical edge bands 382 and 384 of the floating frame member 312 in the manner previously described for the one and seven-eighths inch thick dual panel door. However, at the bottom of the door, as best shown in FIGURE 8, the extruded U-shaped rubber member 376 is mounted in a slotted recess formed in the rail 348, and the adjacent edge band 383 is mounted, as by gluing as indicated at 380, to the bottom edge of the rail 348 and plywood face panel 352 in spaced relation to the spline 374 forming a suitable protective cover member therefor.

In view of the extra thickness of this modified door, it has been found advisable to equip the top of the door with a pair of spaced sealing gaskets 390 and 392. These gaskets are identical to the sealing gaskets previously described and are suitably mounted on a pair of contiguous door stops 394 and 396, respectively (see FIGURE 10). The upper door stop 394 engages the edge band 370 of the main frame member 310, and the lower door stop 396 engages the edge band 382 of the floating frame memher 312. The door stops 394 and 396 are mounted on the inner surface of a conventional door frame 400 by suitable fastening means, such as gluing.

The sides of the door are also equipped with a pair of spaced sealing gaskets 391 and 393, which are mounted in suitable door stops 395 and 397, respectively. The hinge side of the door, as best shown in FIG- URE 9, has an extra Wedging strip 399 mounted, as by gluing, to the inner side of the door frame 400, and the door stop 395 is recessed to receive the same. This construction permits the flanged ends of the sealing gasket 391 to be secured between the inner side of the stop 399 and the adjacent side of the door stop 397.

The bottom of the door, as shown in FIGURE 8, is provided with a corresponding pair of spaced sealing gaskets 404 and 406 adapted to engage a sloping sill 408. The sealing gaskets 404 and 406 are secured by a wooden strip 410 mounted in a recess in the edge band 372, which, in turn, is secured to the rail 322 by any suitable fastening means, such as wood screws 412.

Referring now to FIGURE 11, there is shown the bottom of a door equipped with a spaced pair of conventional drop seals 416 and 418, which are adapted to be used in connection with a flat sill 420.

(V) Modified door of FIGURE 14 Referring now to FIGURE 14, there is shown a modified door of a two and five-eighths inch dual panel construction, which is substantially identical in every respect to the door shown in FIGURES 7 through 12, except that, in this modification, the vertical edge bands 366 and 368 and the horizontal edge bands (not shown but corresponding to the edge bands 70 and 72) are mounted directly on the peripheral edges of the floating frame panel member 312, and the ends 367 of the foam rubber sheeting 365 are turned oppositely to that shown in FIGURE 9, and over the adjacent peripheral edge of the main frame member 310. The U-shaped rubber extrusion member 376 is now mounted in recesses in the main frame 310. The protruding portions of the splines 374 are inserted frictionally into the receiving slots of the rubber extrusion members 376 mounted in the peripheral edges of the main frame member 310. The air space 380 now extends between the edge bands 366 and 368 and the adjacent edges of the main frame 310.

In the door shown in FIGURE 14, a blanket 382 consisting of a mixture of shredded cotton and shredded paper has been substituted for the layer of paper faced styrene 360.

Due to the reversing of the edge bands 366 and 368 in the door shown in FIGURE 14, additional vertically extending stops 384 and 386 are mounted by gluing one each to opposite sides of the outer surface of the panel member 352, which stops provide means for engaging the spaced inner sealing gaskets 393.

(VI) 2 /8" dual swinging doors There is shown in FIGURE 12A a fragmentary view of the present invention incorporated in a pair of swinging doors 440 and 442 in which each is equipped with a vision port or window 444, as shown in detail in FIG- URE 123.

The vision port or window 444 consists of two independent panes of plate glass 210 and 212 suitably secured in window mouldings 21-4 and 216 mounted one on the main frame member 440 and the other on the floating frame member 471. The window mouldings 214 and 216 have a recess or slot 218 out therein into which s fitted a U-shaped rubber extrusion member 220 with its arms extending inwardly. The panes of glass 210 and 212 are mounted with their peripheral edges extending into the slots 222 between the arms of the rubber extrusions 220. Across the inner surfaces of the inner peripheral edges of the window frames 225 and 227 and between the spaced glass panes 210 and 212 there is glued a felt liner 224.

The details shown in FIGURE 12A disclose that the edge bands 450 and 452 are mounted fixedly by gluing on their respective main frame members 454 and 456. The splines 460 and 462 are mounted fixedly on the inner sides of said edge bands with a portion projecting inwardly and into a U-shaped rubber extrusion member 463, which, in turn, is mounted fixedly in the edge bands 466 and 468 of the floating frames 471 and 473, respectively. Manifestly, there is no rigid connection between Icihe main frame and the floating frame members of each oor.

The floating frame member 471 has an astragal 480 mounted thereon by nails 482, and its opposite end projects outwardly beyond the edge band 468 of the opposite swinging door 442. A sealing gasket 484 is mounted on a locking strip 486 which, in turn, is nailed to the astragal 480, providing a resilient means for engaging and sealing the opposite swinging door 442. It will be noted that the opposing edge bands 450 and 452 do not meet or touch each other, but are slightly separated by an air space, which acts as clearance on the pairs of swinging doors.

Vision ports.--Where an airlock is required, which involves the application of two spaced doors, such doors should be of different thicknesses with different natural frequencies so as to obtain the maximum sound reduction.

It will be obvious that in an air lock arrangement, the doors mounted at the opposite ends of the air lock are each provided with a vision port or window. Such vision port or window tends to be more of a custom item, varying considerably in detail from job to job. However, the approximate sound transmission loss required should preferably be included. Such vision ports or windows are used extensively for recording, radio and TV studios and where quiet is required in industry, schools and colleges. Many plants and laboratories, especially those investigating and testing the characteristics of engines, large motors, etc. put them in soundproof rooms and find the ability to observe the equipment in operation through the vision ports or windows most useful. These window or vision ports, which are frequently embodied in a single door construction such as those previously described, are made of two or more panes or lites of plate glass, detuned, mounted in frames either one piece or split, on opposite sides of the door.

The usual size of such vision ports is ten inches by ten inches, and they must be mounted a distance of at least ten inches away from the top or side edges of the door. This is done so the vision port frames will not encroach upon the frames of the door, and to allow a cavity for the acoustical treatments to be applied.

The maximum size for good acoustical results is two hundred and fifty square inches in area. The vision ports or windows must also be placed low enough in the door for short people to see through them. The window lites or panes should be made of plate glass having a thickness of not less than one quarter of an inch. The window frame between the spaced glass panes should be covered with a felt liner, which may be glued to said surface area.

(VII) Utility It has previously been described that the soundproof structures of the present invention are flexible, having a limpness that contributes substantially to their soundproof qualities. This limpness can best be illustrated by laying an assembled door flat on a floor. When it is picked up by one end or one corner, there will be a very decided and perceptible bend adjacent its middle section. With the door in this same position, its floating frame can be moved longitudinally or laterally with respect to the main frame. Such movement shows the total disconnection of the panels and the enhancement of the soundproof qualities of the dual panel construction, and it establishes without doubt the limpness of the doors of the present invention against the rigidity of the conventional soundproof doors of the prior art.

The utility of the present doors may best be compared with the four inch door described and claimed in United States Letters Patent No. 2,880,471, issued Apr. 7, 1959, which is presently being manufactured and sold in direct competition with the present doors, 'but at a much higher price since it has a greater weight due to substantial amount of additional material incorporated therein, and is more difiicult to manufacture in time and labor.

The sound transmission loss ratings of the doors of the present invention and the prior art door described in the preceding paragraph, as established by comparable tests conducted with actual working installations by internationally known and recognized testing laboratories, are as follows:

SOUND TRANSMISSION CLASS RATINGS ASTM 1390-661 1%" door 2% door 4" door 1 1 Patent No. 2,880,471.

I (VIII) Definitions The terms sound vibration insulation maten'a "sound damping and vibration damping have been used to denote materials and methods used to substantially increase that which the physicist calls sound transmission loss, and includes such viscous materials as conventional caulking compounds and the like.

The term limp sheet material has been used to denote any sheet material such as a felt liner, tar paper, a mixture of shredded paper and shredded cotton, roofing materials of the asphalt type, paper backed plastic fibrous materials, such as polyurethane, etc.

The term chipboar is used to denote a board made of chips of wood saturated with glue, pressed into the shape of boards of wood and then dried to form a solid member, which can be cut and shaped like any wooden board.

The term floating frame is used to indicate that the frame carrying recesses and insulated receiving slots is capable of movement longitudinally and/ or laterally upon the application of pressure with respect of the other frame member even after assembly.

The term flexible is used to denote that the soundproof structures are bendable even after assembly, and the term flexibly linked is used to denote that the dual panels are movable or shiftable with respect to one another even after assembly upon the application of pressure at a. peripheral edge thereof.

Although I have shown in detail only a few of the many modifications which the invention may assume, it will be readily apparent to those skilled in the art that many further modifications may be made therein without departing from the spirit thereof or from the scope of the appended claims.

What I claim is:

1. A sound insulating structure comprising a main panel member and a floating frame panel member, said panel members having face spans of different sizes, said face spans being covered with several layers of different sound insulating materials, the peripheral edges of one of said panel members having edge bands mounted fixedly thereon, said edge bands having outwardly protruding splines, the peripheral edges of the other of said panel members having sound insulated recesses opening outwardly towards said edge bands and protruding splines, whereby when said panel members are assembled in superimposed relation with their sound insulating materials juxtaposed the protruding splines of said one panel member will project into the insulated recesses of said other panel member to secure said panel members together into a unitary sound insulating structure.

2. The invention defined in claim 1, wherein the edge bands with their protruding splines are fixedly mounted on the peripheral edges of said main panel member and said sound insulated recesses are embodied in the peripheral edges of said floating frame panel member.

3. The invention defined in claim 1, wherein the edge bands with their protruding splines are fixedly mounted on the peripheral edges of said floating frame panel member and said sound insulated recesses are embodied in the peripheral edges of said main panel member.

4. The invention defined in claim 1, wherein the assembled unitary sound insulating structure is flexible.

5. The invention defined in claim 1, wherein the frame members are flexibly linked together into a unitary sound insulating structure.

6. The invention defined in claim 1, wherein the frame members are flexibly linked together and the resulting unitary sound insulating structure is flexible.

7. A sound insulating structure comprising a main frame member consisting of spaced stiles and spaced rails having an opening therethrough, a face panel of plywood attached to the outer side of said main frame member and covering the same, a plurality of layers of different sound vibration insulating materials covering that portion of the inner face of said face panel closing said opening, a floating frame member consisting of spaced stiles and spaced rails having an opening therethrough of larger dimensions than the opening in said main frame member, a face panel of plywood attached to the outer side of said floating frame member and covering the same, a plurality of layers of different sound vibration insulating materials covering that portion of the inner face of said face panel closing said opening, said main frame member and said floating frame member being superimposed with their peripheral edges aligned and their layers of sound vibration insulating materials juxtaposed, said main frame member having edge bands mounted over the peripheral edges thereof, said edge bands having splines mounted therein with portions thereof projecting inwardly towards said floating frame member, said floating frame member having a series of sound insulated recesses on the peripheral edges thereof opening towards said edge bands of the main frame member, the projecting portions of the splines of the main frame when positioned within the peripheral recesses of the floating frame member securing said frame members together into a unitary sound insulating structure.

8. The invention defined in claim 7, wherein the stiles and rails of said main frame member and said floating frame member are made of chipboard.

9. The invention defined in claim 7, wherein the inner surfaces of the stiles and rails of said main frame member and said floating frame member are covered with a plywood panel member.

10. The invention defined in claim 7, wherein the inner face of said face panel closing the opening in said main frame member is completely covered with said different sound vibration insulating material comprising a layer of viscous sound damping material, wherein the layer of sound damping material is covered with a layer of sheet rock and wherein the layer of sheet rock is covered with a layer of limp sheet material, and wherein the inner face of said face panel closing said opening in the floating frame member is covered with said different sound vibration insulating material comprising a layer of viscous damping material, wherein the layer of viscous damping material is covered with a layer of sheet rock and wherein the layer of sheet rock is covered with a layer of limp sheet material, and wherein the inner face of said panel closing said opening in the floating frame member is covered with a layer of viscous damping material and a layer of polyurethane.

11. The invention defined in claim 7, wherein the stiles and rails of the main frame member and the floating frame member are made of chipboard reinforced at the corners with metal fastening members.

12. The invention defined in claim 7, wherein the plurality of layers of diflferent sound vibration insulating materials comprise a layer of viscous damping material,

a layer of mineral material and a layer of limp sheet material, and said frame members are flexibly linked together into a unitary sound insulating structure.

13. The invention defined in claim 9, wherein when the main frame member and the floating frame member are secured into a unitary sound insulating structure there is an air space between said members substantially coextensive with the layer of limp sheet material covering the free span in said main frame member.

14. The invention defined in claim 9, wherein an air space separates the main frame member and the floating frame member exteriorly of said splines.

15. The invention defined in claim 9, wherein there is a layer of open cell foam rubber separating the main frame member and the floating frame member beyond said layer of limp sheet material.

16. The invention defined in claim 9, wherein the layer of open cell foam rubber separating said main frame member and said floating frame member extends between the peripheral edges of said frame members to the splines which secure said frame members into a unitary sound insulating structure.

17. A flexible and limp sound insulating structure comprising a main frame member consisting of spaced stiles and spaced rails having an opening therethrough, a face panel of flexible plywood attached to the outer side of said main frame member and covering the same, a plurality of layers of different sound vibration insulating materials covering that portion of the innerface of said face panel closing said opening, a floating frame member consisting of spaced stiles and spaced rails having an opening therethrough or larger dimensions than the opening in said main frame member, a face panel of flexible plywood attached to the outer side of said floating frame member and covering the same, a plurality of layers of different sound vibration insulating materials covering that portion of the inner face of said face panel closing said opening, said main frame member and said floating frame member being superimposed with their peripheral edges aligned and their layers of sound vibration insulating materials juxtaposed, said main frame member having a series of sound insulating recesses on the peripheral edges thereof opening towards the floating frame member, and said floating frame member having edge bands mounted over the peripheral edges thereof, said edge bands having splines mlounted therein with portions thereof [projecting inwardly towards said main frame member, the projecting portions of the splines of said floating frame member when positioned within the peripheral recesses of said main frame member flexibly linking said frame members together into a unitary sound insulating structure.

18. The invention defined in claim 17, wherein the inner face of said face panel closing the opening in said main frame member is completely covered with said difierent sound vibration insulating material comprising a layer of viscous sound damping material, wherein the layer of viscous sound damping material is covered with a layer of sheet rock and wherein the layer of sheet rock is covered with a layer of limp sheet material, and wherein the inner face of said face panel closing said opening in the floating frame member is covered with said different sound vibration insulating material comprising a layer of viscous damping material, wherein the layer of viscous damping material is covered with a blanket made from a mixture of shredded cotton and paper.

References Cited UNITED STATES PATENTS 2,880,471 4/1959 Von Munchhausen 52-404 JOHN E. MURTAGH, Primary Examiner US. 01. X.R. 

